David is correct, the core business logic and the way basic functions like MRP, Inventory, Sales and accounting are managed is the same between DBA Classic and Evo-ERP. In fact, in many cases, the exact same program (.RUN file) is being called by both menus. When they are different it is only because of features like the forms editor and RTMs or email capability, not due to functional logic differences.
Check the 10 minute Flash demo at
http://www.istechsupport.com/evolution.asp.
For pricing, it depends on your current DBA Classic License status (lifetime or annual) and whether you are simply converting the seat licenses you have or also adding additional users. Email me directly with that information and I can provide pricingfor you.